Preparation and characterization of chitosan/graphene oxide nanocomposite coatings on Mg–2 wt% Zn scaffold by pulse electrodeposition process

Mg and its alloys are biodegradable and mechanically strong materials, which can be used for an orthopedic implant and device applications, but corrosion rate of these alloys is high. In this research, the nanocomposite coatings of chitosan (CS)/graphene oxide (GO) were fabricated to improve the corrosion resistance of the Mg-2 wt% Zn scaffold. The contents of the GO nanosheets and the pulse electrodeposition process parameters, including peak current density (CD) and duty cycle (DC), will also be investigated. The Mg-2 wt% Zn as a substrate of the scaffold was prepared using a powder metallurgy process. The influence of the porosity was studied on the microstructure fabricated scaffolds. The coating microstructures and morphologies were investigated by Raman spectroscopy, x-ray diffraction, thermogravimetric analysis, and SEM. The atomic force microscopy was performed to study the thickness of the nanocomposite coatings. The zeta potential measurement was conducted for the dispersion of the GO nanosheets in the CS matrix. The obtained results showed that the optimum conditions to fabricate a uniform CS/GO coating on the scaffolds were 2 wt% GO, CD = 20 mA cm-2, and DC = 0.5. The pH, time and temperature for the fabrication of the coatings were conducted at 5, 20 min, and 37 °C, respectively. Additionally, the potentiodynamic polarization measurement in simulated body fluid indicated that the CS/GO coatings could provide effective protection of the scaffolds against corrosion. Additionally, the optimum sample obtained from the aspect of the corrosion behavior demonstrated adequate biocompatibility with proper adhesion of mouse fibroblast cells (L929) on the CS-2 wt% GO coating.